1. Technical Field
The present invention relates to a light source apparatus and a projector, and particularly to a technology for a light source apparatus used in a projector.
2. Related Art
In the field of a light source apparatus for a projector, there has been recently proposed a technology using a laser light source that supplies laser light. A light source apparatus using a laser light source, as compared to a UHP lamp currently used as the light source apparatus for a projector, has various advantages including excellent color reproducibility, quick start, and a long life. Known examples of the light source apparatus using a laser light source include the one that directly supplies fundamental wave laser light from a laser light source and the one that supplies wavelength-converted fundamental wave laser light. As a wavelength conversion element that converts the wavelength of the fundamental wave laser light, for example, a second-harmonic generation (SHG) element is known. Use of a wavelength conversion element along with a general-purpose laser light source easily available allows laser light having a desired wavelength to be supplied. It is also possible to employ a configuration capable of supplying a sufficient amount of laser light. There is a known light source apparatus using an SHG element configured in such a way that the SHG element is disposed in a resonator structure in which the laser light resonates (see JP-A-5-235441, for example). Among the fundamental wave laser light resonating in the resonator structure, extracting laser light having a desired converted wavelength allows laser light to be supplied at high wavelength conversion efficiency.
The resonator structure includes a wavelength selective mirror that reflects the fundamental wave laser light. It is difficult even for a wavelength selective mirror to reflect all fundamental wave laser light, but part of the fundamental wave laser light disadvantageously passes through the mirror. In the configuration proposed in JP-A-5-235441, the fundamental wave laser light that exits from the resonator structure directly leaks out of the light source apparatus. Intense laser light may cause uncomfortable feeling in the human body, particularly in the eyes. A laser light-based apparatus needs to be configured to reliably avoid laser light-related troubles.
A light source apparatus for a projector is, in general, configured to use an SHG element to convert infrared light, which is the fundamental wave laser light, into visible light. It is difficult for the eyes to respond and avoid infrared light compared to visible light. It is therefore necessary to reliably prevent leakage of infrared light, particularly when it is intense. To prevent the leakage of infrared light, it is conceivable to use an infrared light blocking glass member that absorbs infrared light. In the configuration using an infrared light blocking glass member, however, a broken part of the infrared light blocking glass member easily causes the leakage of infrared light to the outside. The related art thus poses a problem of difficulty reliably preventing troubles from occurring in the configuration capable of achieving high wavelength conversion efficiency.